Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight (1) differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; (2) how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and (3) the correlation between frequency of use in the past-month and average grams consumed per use-day. Key findings: focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanics. Further, data from a survey conducted in seven European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations.
Keywords: cannabis, marijuana, substance abuse research, drug use metrics, drug use trends
Citation: Burns RM, Caulkins JP, Everingham SS and Kilmer B (2013) Statistics on cannabis users skew perceptions of cannabis use. Front. Psychiatry 4:138. doi: 10.3389/fpsyt.2013.00138
Received: 31 May 2013; Accepted: 06 October 2013;
Published online: 06 November 2013.
Edited by:Elizabeth Clare Temple, University of Ballarat, Australia
Reviewed by:William Zywiak, Pacific Institute for Research and Evaluation, USA
Copyright: © 2013 Burns, Caulkins, Everingham and Kilmer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Rachel M. Burns, RAND Corporation, Drug Policy Research Center, 4570 5th Avenue, Suite 600, Pittsburgh, PA 15213, USA e-mail: firstname.lastname@example.org